Sealed container and method of manufacturing

ABSTRACT

The present invention relates to sealed containers or pouches. More specifically, the present invention relates to containers, such as flexible packages or bags wherein the containers or pouch can be compressed or evacuated to remove excess air, fluid or other gaseous content and then sealed in such compressed or evacuated arrangement.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. ProvisionalApplication No. 61/060,141 filed Jun. 10, 2008, which is incorporatedherein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to sealed containers. More specifically,the present invention relates to containers, such as plastic bagswherein the containers can be compressed or evacuated to remove excessair, fluid or gaseous content and then sealed in such compressed orevacuated arrangement.

BACKGROUND OF THE INVENTION

Bag like containers have been used to store a large number of materials.One drawback of these devices is that during the filing and sealingprocess, they tend to trap air, fluid or other gaseous materials withinthe confines of the container. This excess gaseous material can make itdifficult to stack the containers and may also contributed to areduction in the amount of product that can be stored, shelved ortransported within a given area. The presence of the gas can alsocontribute, in some instances, to reduced shelf life of the product dueto spoilage.

Paper bags, due to the porous nature of the construction (formed fromcellulosic stock), can allow trapped gases to escape after closure ofthe container, but this venting of the bag is a slow process. Likewise,due to the porous nature of the construction of the paper bags, gasesand moisture can flow back into the container. Hence, spoilage of thecontents can occur due to moisture or in the case of oxygen, oxidationof the contents. Perforations added to the paper container can help inthe expulsion of the unwanted gaseous elements from the container, butmay then contribute to accelerating the process of gases reentering thecontainer.

Plastic bags on the other hand, depending on the materials ofconstruction, provide either a partial or complete barrier to gaseousproducts entering the container, but also create a barrier to removinggases from the closed container. Perforations have been heretofore addedto the containers to facilitate the removal of excess gaseous contents,but again suffer in that these perforations allow later gaseous uptakeby the container. These perforations can also allow contents of smallersize that have a diameter or shape that is smaller than the diameter ofthe perforation to escape from the container. The result is spillage andloss of the overall content of the container.

U.S. Pat. No. 6,378,272 to Archibald proposes a solution to evacuating aplastic container by creating a valve like flap that extends over theperforations. When the gas within the container is expelled, the gaseousflow causes the adhesive affixed to the flap to release from its surfaceand thereby allows the flap to separate from or depart contact withinthe area of the hole and allows the gas to escape. Once the gaseous flowis reduced, the flap can be reaffixed to the surface within the vicinityof the hole and seal the opening so as to retard or prevent the laterentrance to the container by gaseous elements. This design suffers forat least two reasons. First, creation of this flap and placement of theadhesive adds cost to the overall of the construction. Secondly, theadhesive of this device can not have high peel strength or the flap willnot open properly during the evacuation of the container. That, is theflap must be sufficiently releasable from the surface of the container(the adhesive doe not permanently bond to the container) to allow thegas to escape. This ability to easily open may also be a detriment tothe container. Such containers are usually stacked upon each other,transported and then placed in various configurations for sale, such aswith store shelves. The handling of the container and its contact withother surfaces can cause the weakly held adhesive flap to open and henceexpose the contents to the environment, and allow gas, dust or otherdebris to enter the container. Whenever attempts have been made toincrease the peel strength of the adhesive to a valve suited toeliminate inadvertent flap opening, the resultant device did not releaseproperly during container evacuation.

BRIEF SUMMARY OF THE INVENTION

The embodiments of the present invention described below are notintended to be exhaustive or to limit the invention to the precise formsdisclosed in the following detailed description. Rather, the embodimentsare chosen and described so that others skilled in the art mayappreciate and understand the principles and practices of the presentinvention.

This invention provides a method for creating a more economical andeffective way of preparing a container that can be effectivelyevacuated, yet one that can be effectively sealed against gaseous/fluidtransmission with less risk of failure of the sealing mechanism.

In one exemplary embodiment, a method is described for preparing acontainer with perforations that includes the steps of initiallyintroducing a material into the container, then sealing the container.The excess gaseous contents are removed from the container throughevacuation or compression. Finally, a nonporous patch is affixed overthe perforations using a permanent type adhesive resin.

In another exemplary embodiment, an article is described which is acontainer with at least one perforation creating a perforated area andan adhesive patch permanently adhered atop the perforated area.

In a still further exemplary embodiment, substantially quadratecontainer, is presented and includes a pouch that is formed from aflexible sheet material having an oxygen transmission rate of less thanabout 10 cc/100 in (645 cm²)/24 hr/atm at 100° F. The pouch has firstand second longitudinally extending sides and first and secondtransversely extending end edges. The first and second longitudinallyextending sides and transversely extending edges define first and secondoutside surfaces.

Continuing with the presently described embodiment, an exit port isprovided and extends through the first outside surface to a first insidesurface, the exit port has an edge. A porosity mechanism is placedimmediately adjacent the exit port on the first inside surface andsubstantially covers and extends beyond the edge of the exit port. Anadhesive patch is placed over so as to cover the exit port on the firstoutside surface of the pouch. The adhesive patch having a pattern ofadhesive that extends around a perimeter of the adhesive patch andoutside of the edge of the exit port, the adhesive patch furtherincluding a plurality of microperforations having dimensions rangingfrom about 0.2 mm to 0.4 mm.

The embodiments of the present invention described herein are notintended to be exhaustive or to limit the invention to the precise formsdisclosed in the following detailed description. Rather, the embodimentsare chosen and described so that others skilled in the art mayappreciate and understand the principles and practices of the presentinvention.

These and other objects of the invention will become clear from aninspection of the detailed description of the invention and from theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These, as well as other objects and advantages of this invention, willbe more completely understood and appreciated by referring to thefollowing more detailed description of the presently preferred exemplaryembodiments of the invention in conjunction with the accompanyingdrawings, of which:

FIG. 1 is a perspective view of one preferred embodiment of the presentinvention showing a container filled with material prior to removal ofexcess gaseous material;

FIG. 2 is a perspective view of the container being compressed to removeexcess gaseous material;

FIG. 3 is a perspective view of the container with the non porous patchaffixed so as to cover a sole exit port;

FIG. 4 is a perspective view of the container with the non porous patchaffixed so as to cover multiple exit ports;

FIG. 5 is a perspective view of a cross section of the containerillustrating one embodiment which includes a porous filter media; and

FIG. 6 is a flow chart showing an exemplary method for practicing thepresently described invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is now illustrated in greater detail by way of thefollowing detailed description which represents the best presently knownmode of carrying out the invention. However, it should be understoodthat this description is not to be used to limit the present invention,but rather, is provided for the purpose of illustrating the generalfeatures of the invention.

The present invention relates to sealed containers. More specifically,the present invention relates to containers, such as plastic orsynthetic, flexible bags wherein the containers can be compressed orevacuated to remove excess air or fluid content and may be sealed.

FIG. 1 shows pouch or container 10 lying on its side in an orientationsuitable for stacking on a retail shelf for example. FIG. 1 shows thatcontainer 10 includes a main body 11 for holding material 12, the mainbody 11 forming an interior region or a pouch 13 and terminating at aprincipal or top opening 14 sealed with a closure means such a sealingmechanism 15. Body 11 has a flexible outside surface 16 and, oppositeoutside surface 16, inside of pouch 13 an inside surface 17. Extendingthrough pouch 11, from outside surface 16 to inside surface 17, is atleast one exit port 18. These exit ports 18 are typically perforationsor microperforations in the surface of the body 11.

In the case of a pouch 10, one of the exemplary methods that may be usedfor forming the pouch, adding the contents, and sealing the open end ofthe pouch is by using a “Form, Fill, Seal Machine (FFS)”. These machinescan be purchased from various suppliers including Magnum Industries ofKansas City, Kansas and Sandi Acre Packaging Machinery of Nottingham,UK.

Additionally, if the material 12 is of smaller size than exit port 18,that is, the particulate size, shape or diameter is smaller than thediameter of the exit port, a porosity mechanism 19 may be affixed to theinside surface 17 adjacently covering the exit port 18, so as to retainthe material 12 within the container 10.

FIG. 2 shows the container 10 being compressed so as to remove excessgas. It should be noted that alternately a vacuum device (not shown) maybe placed atop exit port 18 so as to withdraw the gaseous content fromthe container.

FIG. 3 shows the container with the non porous patch 20 affixed so as tocover the exit port 18 and preclude further gaseous exchange throughexit port 18.

FIG. 4 shows the container with the non porous patch 20 affixed so as tocover multiple exit ports 21 and preclude further gaseous exchangethrough the exit ports 21.

FIG. 5 shows a side view of the container 10 which further illustratesthe construction and depicts the embodiment wherein the porositymechanism 19 is employed.

The pouch 13 comprises a non-porous flexible material such aspolypropylene and/or polyethylene plastic film. The flexible material islaminated or can be a single layer, multilayer film. The film materialcan be a polymer, co-polymer or melt blends of various plastics. It caninclude construction of foil like materials, either as part of alaminate or as a single layer construction. Material selection should beappropriate for the duration and environmental exposure anticipatedduring the product life cycle. For instance, if the container is outsidein a tropical environment, the container would need to be UV andmoisture stable in order to withstand the exposure to sunlight andhumidity respectively. Likewise, the container should be inert to thechemical contents contained therein. Fertilizers, oxidizers andcorrosive materials are good examples. Other examples of environmentalconsiderations might include resistance to insects and mites.

Sealing mechanism 15, in a closed position, prevents the material 12from exiting pouch 13 as illustrated in FIG. 1. When a sealing mechanism15 is closed, principal opening 14 is also closed. A sealing mechanism15 can comprise a resealable sealing mechanism such as the zippermechanism found on Zip-Loc® brand storage bags available from the GladProducts Company (www.glad.com) or a permanent seal such as a heatsealing of the principal opening 14.

In one embodiment, a porosity mechanism 19 is utilized. This mechanismfunctions to allow excess gaseous contents, but not other material 12 inpouch 13, to be expelled when the container is squeezed, i.e., forcedout of pouch 13 or placed under vacuum to withdraw the gaseous material.The excess gas passes through porosity mechanism 19 out through exitport 18 to form an aspirated container.

Porosity mechanism 19 can have a different porosity depending on thesize of the particle 12 being stored in pouch 13. The larger theparticles 12, the greater the porosity can be of porosity mechanism 19.Some examples of possible porosity mechanisms 19 would be perforatedstrips and non-woven or spun bonded fabrics. Preferably, a porositymechanism 19 has a construction or design so that it does not becomeclogged with particulate material which could impede the expiration ofthe entrapped air 12 when excess gas is squeezed out of pouch 13. Thatis, particulate material may be picked up by the gas/fluid flow andcarried to the exit port.

The non-porous patch 20 can be made out of the same material as thecontainer or may be constructed of other materials that provide theneeded flexibility and barrier properties required. The non-porous patchmay be constructed of polymer flexible film or foil films. Alternatelythe non-porous patch 20 can be constructed of a porous material such aspaper, which may either be coated with a sealing material, such assilicone or wax or the adhesive may be sufficient impermeable to preventgas/fluid flow through the paper.

The adhesive layer of the non-porous patch 20 is selected so as toprovide sufficient tack at expected use temperatures (temperaturesranging from about 55° F. to about 100° F. or those found in warehouses,retail outlets and some transport configuration). These adhesives willrapidly build bond strength in a short period of time to achieve apermanent bond which precludes removal of the non-porous patch 20. Theadhesive coverage on the surface of the patch 20 may be complete or itmay partially cover the surface of the patch 20. It is preferablehowever that the adhesive area around the perimeter of the patch 20 becontinuous so that no pathway exists for gas to pass between the patch20 and the surface of the container or pouch 10. The adhesive can be apressure sensitive adhesive, heat activated adhesive, or heat appliedadhesive. Alternatively, a pattern of adhesive may be used, such asoverlapping strips or segments which still create an effective sealagainst air or gaseous egress or ingress.

FIG. 6 shows in block diagram form the steps involved in exemplaryembodiment. First, a pouch with an imperforate structure 100 is created.Material is 7 then introduced into the pouch 200 and the material entrypoint is sealed 300. The excess gas within the pouch is then removed 300via a method as previously described. The pouch is then sealed byaffixing a patch, as previously described, atop the imperforatestructure.

The amount of pressure-sensitive adhesive employed in theseconstructions may range from about 1 to about 100 grams/m², and moreoften, the amount is in the range from about 15 to about 45 grams/m²,and still more preferably 15 to about 30 grams/m². A variety ofpressure-sensitive adhesives can be utilized including hot-meltadhesives, water-based adhesives such as water soluble or waterdispersible adhesives, and solvent-based or organic soluble adhesives.Such adhesive compositions are described in, for example, “Adhesion andBonding”, Encyclopedia of Polymer Science and Engineering, Vol. 1, pages476-546, Interscience Publishers, 2nd Ed. 1985 and are available fromAvery Dennison Corporation, Pasadena, Calif. Such compositions generallycontain an adhesive polymer such as natural, reclaimed orstyrene-butadiene rubber, styrene butadiene or styrene isoprene blockcopolymers, polyisobutylene, poly(vinyl ether) or poly(acrylic) ester asa major constituent. Other materials may be included in thepressure-sensitive adhesive compositions such as resin tackifiersincluding, for example, rosin esters, oil-soluble phenolics, orpolyterpenes; antioxidants; plasticizers such as mineral oil or liquidpolyisobutylenes; and fillers such as zinc oxide or hydrated alumina.

In applications where moisture sensitivity of the product is an issue, alow moisture vapor transmission rate (MVTR) adhesive can be employed.Preferably, the adhesive layer has a moisture vapor transmission rate(MVTR) of less than 10 g/(m²*24 h), preferably of less than 1.1 g/(m²*24h), measured according to DIN 53122 at a temperature of 23° C. and arelative humidity of 85%. These tests can be performed using a HoneymoonModel W 825 Water Vapor Transmission Rate Tester (Honeywell, Inc.,Minneapolis, Minn.).

In applications where oxygen sensitivity of the product is an issue, alow oxygen transmission rate (OTR) adhesive can be employed. Preferably,the adhesive layer has an oxygen permeability rate of less than about 10cc/10 in (645 cm²)/24 hr/atm at 100° F. (38° C.), more preferably, lessthan about 1.0 cc/100 in (645 cm²)124 hr/atm at 100° F. (38° C.). Theaforesaid oxygen transmission rates can be determined by various methodsknown in the art. For example, these rates can conveniently be measuredwith a Dohrmann Polymeric Permeation Analyzer, PPA-I (DohrmannEnvirotech Corporation, Mountain View, Calif.). The Dow Cell can also beemployed for this purpose, in accordance with ASTM procedure D-1434.

In some applications it may be desired to have very small vent holes(exit ports). The desire for these small vent holes may be due tocosmetic or structural considerations or may be used as a retentiondevice when small particle size contents are present. In theseapplications microperforations may be required. Microperforationsinclude slits or round holes having a maximum dimension of about 0.2-0.4millimeters. In a preferred embodiment of the invention, perforationscomprise slits or round holes having a maximum dimension of about 0.3millimeters so that they are essentially invisible to the naked eye.These microperforations can be made via mechanical puncturing methodsbut can also be made using lasers. Examples of microperforations includeU.S. Pat. No. 5,171,593 to Doyle, U.S. Pat. No. 5,405,561 to Dais andU.S. Pat. No. 6,146,731 to Tanoto.

The pouch structures of this invention can be prepared from sheets ofmaterial which are folded upon themselves in any number ofconfigurations. Seams are typically glued or welded together. Likewisethe pouches can be constructed from cylindrical tubes of material. Thesetubes, for example, can be prepared using a circular extrusion die withair introduced internal to the tube in order to prevent collapse of thetube prior to cooling of the film. These “blown films” are well known inthe industry. By collapsing the tube to a flat structure, cutting tosuitable length and by sealing the open end, a pouch can be constructed.Examples of blown films include EP 1111B 1 to Pannenbecker and U.S. Pat.No. 4,354,997 to Mizutani.

It will thus be seen according to the present invention a highlyadvantageous container has been provided. While the invention has beendescribed in connection with what is presently considered to be the mostpractical and preferred embodiment, it will be apparent to those ofordinary skill in the art that the invention is not to be limited to thedisclosed embodiment, and that many modifications and equivalentarrangements may be made thereof within the scope of the invention,which scope is to be accorded the broadest interpretation of theappended claims so as to encompass all equivalent structures andproducts.

The disclosures of all patents mentioned herein are hereby incorporatedby reference and may or may not be prior art.

The inventors hereby state their intent to rely on the Doctrine ofEquivalents to determine and assess the reasonably fair scope of theirinvention as it pertains to any apparatus, system, method or article notmaterially departing from but outside the literal scope of the inventionas set out in the following claims.

1. A method for making a sealed container comprising the followingsteps: providing a pouch structure, the pouch structure including ahousing having first and second ends and first and second longitudinallyextending sides, each of the first and second ends are sealed to createa closure having an interior and an exterior; the housing furtherincluding at least one perforation creating a perforated area and theperforated area is covered by an adhesively secured patch permanentlyadhered atop the perforated area; introducing a material into the pouch;sealing an open end of the pouch; placing the adhesive patch atop theperforated area of the pouch; removing gas from the pouch via the atleast one perforation by compressing the pouch; and sealing the pouch.2. A method recited in claim 1, wherein the patch is non-porous.
 3. Amethod recited in claim 2, wherein the patch is constructed from aporous material provided with an impermeable coating such as adhesive.4. A method recited in claim 1, wherein the adhesive has a low moisturetransmission rate.
 5. A method recited in claim 1, wherein the adhesivehas a low oxygen transmission rate.
 6. A method recited in claim 1,wherein the step of removing the gaseous contents is done by mechanicalcompression of the sealed pouch.
 7. A method recited in claim 1, whereinthe step of removing the gaseous contents is done by applying a vacuum.8. A method recited in claim 1, including a further step of placing aporosity mechanism adjacent the perforated area such that it preventsescape of the non gaseous contents of the container during the step ofremoving the gas.
 9. A method recited in claim 5, wherein the adhesivelayer has a moisture vapor transmission rate of <1.1 g m²*24 h).
 10. Anevacuatable container, comprising: a housing having first and secondends and first and second longitudinally extending sides, each of thefirst and second ends are sealed creating a closure having an interiorand an exterior; the housing further including at least one perforationcreating a perforated area; the perforated area is covered by anadhesive patch permanently adhered on top of the perforated area; andwherein the adhesive patch prevents gaseous exchange between theinterior and exterior of the container.
 11. An article recited in claim11, wherein at least one perforation is a micro perforation that has adiameter of about 0.2 mm to about 0.4 mm.
 12. An article recited inclaim 11, wherein the adhesive has a low moisture transmission rate. 13.An article recited in claim 11, wherein the adhesive has a low oxygentransmission rate.
 14. An article recited in claim 11, including aporosity mechanism placed adjacent to the perforated area on theinterior portion of the container.
 15. An article as recited in claim11, wherein the adhesive has a chemical resistance to contents providedin the container.
 16. An article as recited in claim 11, wherein thesurface of the container has a series of irregularities and the adhesiveforms a tight seal to the surface.
 17. An article as recited in claim11, wherein the article is comprised of materials resistant toenvironmental degradation.
 18. An article as recited in claim 11,wherein the adhesive patch is provided with a perimeter pattern ofadhesive.
 19. An article as recited in claim 11, wherein a pattern ofadhesive is used, and the adhesive for the adhesive patch is selectedfrom a group that includes hot-melt adhesives, water-based adhesives,solvent based or organic soluble adhesives.
 20. A substantially quadratecontainer, comprising; a pouch formed from a flexible sheet materialhaving an oxygen transmission rate of less than about 10 cc/100 in (645cm²)/24 hr/atm at 100° F., the pouch having first and secondlongitudinally extending sides and first and second transverselyextending end edges, the first and second longitudinally extending sidesand transversely extending edges defining first and second outsidesurfaces; an exit port extending through the first outside surface to afirst inside surface, the exit port having an edge; a porosity mechanismis placed immediately adjacent the exit port on the first inside surfaceand substantially covers and extends beyond the edge of the exit port;and an adhesive patch placed over and covering the exit port on thefirst outside surface of the pouch, the adhesive patch having a patternof adhesive extending around a perimeter of the adhesive patch andoutside of the edge of the exit port, the adhesive patch furtherincluding a plurality of microperforations having dimensions rangingfrom about 0.2 mm to 0.4 mm.